[ARC5] Why an UNUN?

[J. Forster]

The 13 seems a bit high. Is there a lower limit given also? I don't have
that manual to hand.

Best,

-John

==========


> The manual gives a range of values, John.  The upper limit is around 13
> ohms resistive, but it also expects a capacitive component.  See para
> 1-28 in the ARC-5 manual, although the SCR-274-N and ATA manuals contain
> the same data, IIRC.
>
> On 10/24/2012 6:06 PM, J. Forster wrote:
>> Where did the 12 Ohms, resistive, come from? A manual? The value of a
>> dummy load? Where?
>>
>> -John
>>
>> ===========
>>
>>
>>> I gather, then, that the ARC-5 and SCR-274 transmitters
>>> are designed to work into an impedance around 12 Ohms?
>>> And therefore, addition of the 4:1 Un-Un will allow the
>>> command sets to load properly into the usual dipole?
>>>
>>> * * * * * * * * * * *
>>> * 73 - Mac, K2GKK/5 *
>>> * (Since 30 Nov 53) *
>>> * k2gkk at hotmail.com *
>>> * Oklahoma City, OK *
>>> * USAF & FAA (Ret.) *
>>> * * * * * * * * * * *
>>>
>>>
>>>> From: brianclarke01 at optusnet.com.au
>>>> To: arc5 at ix.netcom.com
>>>> Date: Thu, 25 Oct 2012 08:22:30 +1100
>>>> CC: arc5 at mailman.qth.net
>>>> Subject: Re: [ARC5] Why an UNUN?
>>>>
>>>> And a third reason, Dave,
>>>>
>>>> You can fit an appropriate Unun inside the BC-442 or equivalent.
>>>>
>>>> And the turns ratio of the unun will be 2:1 because you require 24 V
>>>> across 50 Ohm to deliver 12 W. Using a small ferite core can allow
>>>> this
>>>> unun to cover most of the ham bands that Command sets can work - 160,
>>>> 80
>>>> and 40. So, no need for external components or any per set
>>>> modifications.
>>>>
>>>> 73 de Brian, VK2GCE.
>>>>
>>>>> David Stinson <arc5 at ix.netcom.com> wrote:
>>>>>
>>>>>
>>>>> Found a WiFi hot spot for my laptop. :-)
>>>>>
>>>>> Couple of reasons for using the series cap
>>>>> and broadband UNUN:
>>>>>
>>>>> Assuming a resonant antenna, does not require
>>>>> one to build and/or add an external tuning network.
>>>>> More important: It's simple, easy and cheap.
>>> ______________________________________________________________
>>> ARC5 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ARC5 at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>>
>>
>> ______________________________________________________________
>> ARC5 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ARC5 at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>>
>
>